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-   -   How many wires in 1/2" conduit? (http://www.diychatroom.com/f18/how-many-wires-1-2-conduit-17590/)

alvanos 02-24-2008 09:38 PM

How many wires in 1/2" conduit?
 
I want to make sure I'm not creating any code violation; I'm currently feeding (at the maximum point) 8 wires through my conduit. They quickly reduce after the initial point, but I want to make sure I'm not breaking any code. I live in Buffalo Grove, a suburb of Chicago.

Tx!

chris75 02-24-2008 09:41 PM

Quote:

Originally Posted by alvanos (Post 101406)
I want to make sure I'm not creating any code violation; I'm currently feeding (at the maximum point) 8 wires through my conduit. They quickly reduce after the initial point, but I want to make sure I'm not breaking any code. I live in Buffalo Grove, a suburb of Chicago.

Tx!

What size wires and what type of conduit, and how many are current carrying conductors? in layman's terms what are the wires doing/feeding.

alvanos 02-24-2008 09:51 PM

Quote:

Originally Posted by chris75 (Post 101409)
What size wires and what type of conduit, and how many are current carrying conductors? in layman's terms what are the wires doing/feeding.

Oops, details! :whistling2:

14 guage wires. 1/2" EMT/thinwall. Four pairs of hot/neutral.

chris75 02-24-2008 10:06 PM

Quote:

Originally Posted by alvanos (Post 101417)
Oops, details! :whistling2:

14 guage wires. 1/2" EMT/thinwall. Four pairs of hot/neutral.

using the emt as the ground?

BigJimmy 02-24-2008 10:17 PM

The code is written according to what's safe, but not necessarily what's practical. That being said, according to Table C1 in annex C of the NEC, you can put 12 single conductor 14 awg. THHN wires in a 1/2 emt. There is a physical limitation though. If I designed according to this, the electricians would skin my hide!

Don't forget the de-rating factor. Assuming 14 awg. THHN, 8 conductors in a single pipe would require a 70% derating so you should be fine with 15A circuit breakers.

Since you have another post about the number of bends, I'd keep them to a minimum if you're pulling 8 conductors. Remember that you can install 1900 boxes along the way. You'll be happy you did.

TTFN.
Jimmy

BigJimmy 02-24-2008 10:18 PM

Quote:

Originally Posted by chris75 (Post 101422)
using the emt as the ground?

Here in Chicago, using the pipe as ground is common/allowed but I'll let the OP comment.

Kingsmurf 02-24-2008 10:27 PM

kingsmurf
 
go buy two books . .one is a Home Depot Residential witring book and a little yellow book called . . .UGLY'S . . .yup I dont make this stuff up
. .it is our quick reference for conductor fill etc . . .you'll find both quite useful . . .

Speedy Petey 02-25-2008 05:54 AM

Quote:

Originally Posted by BigJimmy (Post 101436)
Here in Chicago, using the pipe as ground is common/allowed but I'll let the OP comment.

It certainly is, but it is also generally accepted that this is not a good practice to follow.
Conduit fittings can become loose over time form many reasons.
I personally NEVER relay solely on a metallic conduit for a ECG.

wire_twister 02-25-2008 06:12 AM

Amen Petey,
I pull an equipment grounding conductor in every pipe I run even if it is rigid pipe.

BigJimmy 02-25-2008 01:32 PM

Twister and Pete:

Sorry, I was thinking totally in the realm of residential. I typically do not see a dedicated wire being run as an EGC in this application (here anyways) however I do agree that there's merit to doing so.

On the other hand, I do run a ground wire through greenfield.

Take care

goose134 02-25-2008 09:31 PM

Quote:

On the other hand, I do run a ground wire through greenfield.
That is good Jimmy, because you are required to do so.
To everyone else, as Jimmy said, in residential construction, EMT is the ground. Connectors can come loose over time, but it isn't likely if you tighten everything properly. Commercial is a different story.

While my mind is on this, Petey have you noticed more specs calling for steel fittings? The last couple of years seems like everyone wants steel instead of zinc.

goose134 02-25-2008 09:32 PM

I almost forgot the other thing: Chicago allows NO MORE THAN 9 wires in a pipe. Current carrying or not. (Unless it's a control circuit)

chris75 02-25-2008 09:59 PM

Quote:

Originally Posted by Speedy Petey (Post 101488)
It certainly is, but it is also generally accepted that this is not a good practice to follow.
Conduit fittings can become loose over time form many reasons.
I personally NEVER relay solely on a metallic conduit for a ECG.

I agree and disagree. Its a proven fact that the conduit is a better ground then any wire pulled through it, I dont see a fitting just coming loose, its either tight or someone loosened it, but what ever, I always pull a EGC...

nap 02-25-2008 10:31 PM

I have seen loose fittings, especially a whole bunch of compression fittings a few years ago. It seems that they never tightened up due to the pipe not being in perfectly straight. Lots of 'em.

I also work in the land of the mobile home capitol and they are terrible as far as damaging things. Broken pipe all over the place that since it is seperated, it no longer provides an adequate ground. The EGC inside takes care of that.

goose, have you checked prices lately. die-cast were about 3 times the cost of the steel fitting a while back. Had a run of very poor quality steel fittings about 7 years ago. Kind of turned me off of them. The ones around here now are pretty good and I actually prefer them.

and to the EGC is Greenfield. Haven;t looked lately 'cuz I always drag one along anyway but I thought that sections under 6 feet didn;t need an EGC (except in Michigan where one is always required in Greenfield)

InPhase277 02-25-2008 11:22 PM

Quote:

Originally Posted by goose134 (Post 101789)
That is good Jimmy, because you are required to do so.
To everyone else, as Jimmy said, in residential construction, EMT is the ground. Connectors can come loose over time, but it isn't likely if you tighten everything properly. Commercial is a different story.

While my mind is on this, Petey have you noticed more specs calling for steel fittings? The last couple of years seems like everyone wants steel instead of zinc.

I saw a picture once of a UL test that showed different fittings under a ground fault test. The zinc fittings failed and melted before the steel fittings. Perhaps that has something to do to it.

InPhase277


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